Spa brush



FIG. 1 is a front-top-right perspective view of a spa brush showing mynew design;

FIG. 2 is a front-bottom-right perspective view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines in the figures illustrate portions of the spa brushthat form no part of the claimed design.

CLAIM The ornamental design for a spa brush, as shown and described.